Last week we launched Reading Journals which allow you to do exactly this!

Book notes, inspired by these:
https://sive.rs/book
https://www.nateliason.com/notes

Also some place to save favorite quotes or similar

The concept of being able to take more notes on a book is one I'm also very interested in. I've struggled to keep track of my notes, but having them in one place with my book data would be great. Definitely considering this!

Adam